Questions on Facebook PPC Advertising

Hello!
I am relatively new to PPC ads, although I understand the concept. I was just curious if people tend to break even or profit? I know there are dozens of factors here, I'm just looking for some opinion based on experience.

Also, I notice there is a minimum bid option when setting up an ad and I do not have much of a budget. If My monthly budget is set to, say, $40, would that cap out at 4o no matter what or do bids still happen? I just don't want to set this up and then have a $300 CC bill.

If you set a budget, it will stick to your budget. The most you'd go over if it happened is a couple of bucks.